This invention relates to a deflection unit within which a line deflection coil system is arranged, said line deflection coils being connected in an electric circuit to a line balance coil arrangement comprising a cylinder which is provided with two sub-coils and within which a magnet core is arranged.
In deflection units for cathode ray tubes, such as display tubes, and particularly monitor tubes and television tubes, line balance coils are used to control the selfinduction balance between the two line deflection coils. To this end, they are incorporated in a circuit with the line deflection coils. The line deflection coils are preferably arranged within a hollow synthetic material coil support.
The conventional line balance coil comprises two sub-coils wound on a cylinder. The cylinder is an injection-moulded product of polycarbonate in which 4 wires are moulded, while at one end the coil is sealed and at the other end the wire is inserted into a PCB (Printed Circuit Board) and soldered. The PCB has "riveting bushes" which are used for security purposes. The PCB is the connection between contact pins G, H of the line balance coil and the contact pins A, D to which the line deflection coils are connected. The PCB also ensures the connection between the line balance coil and the client connection E. The other client connection is B or C (see FIGS. 1, 2 and 4). In practice, these types of line balance coil-PCB constructions present problems which may even lead to fire. According to the invention, these problems are related to differences in expansion between PC (polycarbonate) of the coil cylinder and the PCB material, while the mode of establishing electrical contact via wires soldered in riveting bushes is not optimal.